New Class of Supramolecular Bowl-Shaped Columnar Mesogens Derived from Thiacalix[4]arene Exhibiting Gelation and Organic Light-Emitting Diodes Applications.

Vinay S Sharma,Priyanka A Shah,Anuj S Sharma,Pranav S Shrivastav,Mohd Athar,Akshara P Shah

doi:10.1021/acsomega.9b01776

Abstract

A new class of blue light-emitting bowl-shaped mesogens with the thiacalix[4]arene core appended with 1,3,4-thiadiazole derivatives having peripheral alkoxy side chains have been synthesized and well characterized. The liquid crystalline behavior of present synthesized derivatives was examined by optical polarizing microscopy, differential scanning calorimetry, and X-ray diffraction studies. It was observed that these thiacalix[4]arene derivatives were capable of stabilizing the observed Colh phase with a higher temperature range. The cone-shaped thiacalix[4]arene-based liquid crystals with peripheral alkoxy side chains able to pack into the columns with enriched intermolecular interactions and thermal behavior. All derivatives showed blue luminescence in solution, solid thin-film, and gelation state. The hexagonal columnar phase and emissive nature of thiadiazole-based thiacalixarene compounds having xerogel behavior make them favorable in the application of emissive electronic display devices. The electrochemical properties of these thiacalixarene-based compounds demonstrate the effect of alkyl side chain on the highest occupied molecular orbital–lowest unoccupied molecular orbital energy levels and also exhibited lower electron band gaps. The electroluminescence behavior of the compound 10c was examined as emissive layers in the fabrication of organic light-emitting diodes.

Highlights

In recent years, the liquid crystal of self-organizing molecular systems with multifunctional properties is one of the most attractive and active fields of current research
organic light-emitting diodes (OLEDs) are monolithic solid-state devices that typically consist a series of organic thin films sandwiched between two thin-film conductive electrodes which display a substantial part in the growth of new flat-panel displays
Small OLED panels are used for the displays of mobile phones, while large OLED panels are popular in displays of television, mirror display, transparent display, and signage.7−9 Nowadays, it is accepted that OLEDs will become the governing technology in the display market

Summary

■ INTRODUCTION

The liquid crystal of self-organizing molecular systems with multifunctional properties is one of the most attractive and active fields of current research. The bowl-shaped di-substituted thiadiazole thiacalix[4]arene-based columnar liquid crystalline derivatives (10c, 10d) showed gelation properties in nonpolar solvents which are formed by Π−Π interactions and the presence of H-bonding. From the 1H NMR, compounds 10a−10d exhibited a pair of singlets for the −C(CH3) group on the thiacalixarene core with the presence of two singlets for aromatic hydrogen indicates the substitution of thiadiazole Schiff-base derivatives on lower rim to form stable cone confirmation that displays columnar hexagonal liquid crystalline properties.. The realignment of the gelator fibers in the supramolecular structure of the bi-substituted thiacalix[4]arene derivatives in decane and dodecane clearly indicates the formation of the network structure in the organogels because of the presence of hydrogen bonding between −CH N and −OH groups at the lower part of the thiacalixarene core. It can be noted that as the dopant ratio varies from 1 to 6 wt %, the dye did not display any variations in EL maxima and CIE coordinates probably suggest that the bowlshaped molecules become aggregate to repel uniformly at higher concentrations.

■ CONCLUSIONS

General Method for the Preparation of Compound

■ ACKNOWLEDGMENTS

Findings

■ REFERENCES